Which of the following numbers is a multiple of 5? ${60,63,66,68,82}$
Answer: The multiples of $5$ are $5$ $10$ $15$ $20$ ..... In general, any number that leaves no remainder when divided by $5$ is considered a multiple of $5$ We can start by dividing each of our answer choices by $5$ $60 \div 5 = 12$ $63 \div 5 = 12\text{ R }3$ $66 \div 5 = 13\text{ R }1$ $68 \div 5 = 13\text{ R }3$ $82 \div 5 = 16\text{ R }2$ The only answer choice that leaves no remainder after the division is $60$ $ 12$ $5$ $60$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $5$ are contained within the prime factors of $60$ $60 = 2\times2\times3\times5 5 = 5$ Therefore the only multiple of $5$ out of our choices is $60$. We can say that $60$ is divisible by $5$.